(Post Master Sr)

04/15/13 01:26 PM

Is wheel horsepower = wheel horsepower

Here is an interesting question I’ve been thinking about lately. Does x rwhp = x awhp? I know that there is more drivetrain loss through 4 wheels, which is why most people calculate it as 22% loss rather than 15% for 2 wheel drive car. So, given that x rwhp = x awhp, all wheel drive car should make more power at the engine. But the question is not about the engine, but rather the car itself. Let’s eliminate traction as a variable, and say that the car is a same car making same power from the same motor. Would they be equally fast, if both of them made same WHEEL horsepower, regardless of being AWD or 2WD? I want to say yes, but I’m not 100% certain on this.

NVMYMPGZ

(Sr Member)

04/15/13 05:17 PM

Re: Is wheel horsepower = wheel horsepower

I try to keep things simple. The motor makes the power, AWD vs RWD vs FWD. No matter. The motor sends power to the drivetrain which accounts for the % of loss.

Typicality speaking, automagic will produce more loss, same goes for any system that tries to power more than 1 axle.

The motor power is the same, the power that makes it to the ground is where the difference lies

UglyValiant

(Post Master Sr)

04/15/13 07:13 PM

Re: Is wheel horsepower = wheel horsepower

If the question is "will an AWD and RWD car, assuming same traction/no spin and same weight, gears, etc, were making the same HP to the wheels, will they be equal in a race?"

then yes.

If it were "same weight, all the above, same power at the flywheel, and same zero traction issues for either, would the two be equal?"

then no, as more power would be lost to the wheels of the AWD, and it would be slightly slower.

g96nt

(Jr Poster)

04/29/13 08:10 AM

Re: Is wheel horsepower = wheel horsepower

Yeah.
Assuming you had 2 cars that weigh the same and have the same WHP, you'd end up with pretty similar MPH. (removing traction as a variable)
Although the AWD might be quicker, they'd both end up with pretty similar trap speeds, which is the true(r) measure of power.

Dynam

(Newbie)

05/02/13 10:38 PM

Re: Is wheel horsepower = wheel horsepower

i think youu are right.but a little difficult with you.the 2 wheel drive aim at speed than power.Nine-Eagles